Investigations were conducted with commercial-type peanut shellers to determine the effects of several variables of mechanical shelling on seed germination. The investigated variables were types of shellers, grate design, cylinder design, direction of cylinder rotation, radial distance between cylinder and grates, cylinder speed, and techniques of feeding peanuts into the sheller. Statistical analysis of the data indicated that only the effects of cylinder speed were statistically significant. Although the effects of feed techniques were not statistically significant, it appeared that some feed techniques lowered the germination by several percentage points. Operating commercial-type shellers so as to obtain a maximum whole-seed outturn and treating the shelled peanuts with the fungicide immediately after shelling minimized the detrimental effects of mechanical shelling on germination.